An article having a layer containing nonconductive organic fibers and method of producing

ABSTRACT

This invention pertains to a composite layered article and to a method for producing the article. The article consists of a body having an electrically conductive layer containing nonconductive organic fibers and a layer of chromium exterior to the fiber containing layer. There may be a metal layer intermediate the body and the organic fiber containing layer. The layers may be deposited electrolytically.

United States Patent Odekerken 14 1 Mar. 28, 197 2 [54] AN ARTICLEHAVING A LAYER 3,152,972 10/1964 Brown ..204/4l NONCONDUCTWE 222222221222 ----22:22 ORGANIC FIBERS AND METHOD OF 3:268:424 8/1966 Brown .1:IIII204/41 PRODUCING 3,356,467 12/1967 Brown .204/41 1,608,694 11 1926Cai 29 196.6 [721 Mark odekerken, 8 Nether- 2,613,304 1oi1952 c6131....2 9/19s lands 2,792,624 5/1957 Muller.... .....29/l9l.2 Assignee: N. vResearch Holland g g Hep Fahey mgenbosch Netherlands 7 PrimaryExaminer-Hyland Bizot [22] Filed: Oct. 23, 1965 Attorney-Waters, Roditi,Schwartz & Nissen This invention pertains to a composite layered articleand to a [52] U.S.Cl ..29/l95 P, 204/41, 204/38 B, method f producingthe i h article consists f a 29/196-6, 29/194-2 body having anelectrically conductive layer containing non- [51 Int. Cl ..B32b 15/00conductive organic fibers and a layer of chromium exterior to [58] Fieldof Search ..29/ 196.6, 194, 191.2; 204/40, the fiber containing layer.There may be a metal layer inter- 204/41 mediate the body and theorganic fiber containing layer. The

layers may be deposited electrolytically. [56] References Cited 18Claims, 2 Drawing Figures UNITED STATES PATENTS 3,152,971 10/1964Tomazewski 204/41 PATENTEDHAR28 m2 3,652,236

AN ARTICLE HAVING A LAYER CONTAINING NONCONDUCTIVE ORGANIC FIBERS ANDMETHOD OF PRODUCING Nonconducting materials to improve the Corrosion Re-10 sistance of Nickel-Chromium Electrodeposits," published inElectroplating and Metal Finishing, Volume 17 No. 1, Jan. 1964, pages2-1 1, to produce microporous chromium deposits by applying onto anarticle, before the same is chromium-plated, metallic layers containingsolid, nonconductive substances. As described on page 4 of the abovepublication, a disadvantage of this method is that the particle size ofthe nonconductive substances should be below about l microns, or theplating will have a rough surface.

lt is an object of the invention to overcome the need for the use ofsolid nonconductive substances of small particle size in order to insurea smooth surface.

It is a further object of the invention to replace the known solidnonconductive substance with a class of substances which need not be ofany specific prohibitive minimum size in order to confer a smoothsurface finish to the protective layer.

Yet another object of the invention is to employ a class of substancesas above-mentioned which are relatively inexpensive and readilyavailable.

Still another object of the invention is to provide a relatively brightfinish even when the content of the aforesaid class of substances isrelatively high in order to produce an optimum microporous structure.

ln accordance with the invention, it has been surprisingly found thatthe difficulty with regard to the small size required for the solidparticles in order to insure smoothness of the plating can be overcomeif the nonconductive materials which are used are organic fibers, aswill be described hereinafter in greater detail.

Organic fibers may be subdivided into the following classes:

1. natural fibers 2. semi-synthetic fibers 3. synthetic fibers.

The class of natural fibers includes substances such as cotton(cellulose), wool (creatin), silk (chief ingredient fibroin, andalbuminoid) kapok, flax, down, fur and the like.

The class of semi-synthetic fibers comprises fibers made syntheticallyfrom natural products, such as fibers produced from cellulose. Includedin this class are also rubber fibers made from natural rubber.

The class of synthetic fibers includes fibers of polyamides polyesters,polyvinyl compounds, Latex, Kel F, silicons and the like.

The natural fibers usually having a thickness of 10-50 microns, thesemi-synthetic fibers a thickness of 5-50 microns, and synthetic fibersare available with a thickness as small as 0.3 microns. The fibers withthe above thicknesses are all effective for achieving their function asnonconductive materials, as will be shown more fully hereinafter. Thelength of the fibers can be determined by the user, since modern cuttingdevices afford accurate cutting of the fibers to a length of 5 microns.A very large number of organic fibers are commercially available in asufficiently high grade; cellulose fiber, for example, is available invarious lengths ranging from 40-1 microns under the name of Solka-Floc.

We have now discovered that these organic fibers, as describedhereinbefore, in lengths ranging from 10 microns to as long as 300microns, are an ideal expedient for producing microporous chromiumdeposits. The organic fibers may be directly used in a bright nickelbath, a semi-bright nickel bath or in a matte nickel bath. The chromiumlayer which is superposed will then be microporous and have a finishwhich is lustrous, semi-lustrous or matte. The open structure of thechromium plating can be determined by means of the Dubpernell test(Proc. American Electroplaters Soc. 1928, page 338).

When the content of organic fibers is increased to produce an optimummicroporous structure, this will affect the luster if a bright nickelbath is used. There is first obtained a cloudy effect, and when thecontent of organic fibers is further increased, a uniform satin-likenickel deposit is obtained. Obviously, such a bath is unsuitable forproducing a bright nickel deposit. It is, however, possible to firstapply a bright nickel layer by means of a bright nickel bath which isfree of fibers, and then apply a thin layer of a thickness, for example,of 0.1-3 microns, by means of a bright nickel bath having a high contentof fibers, so that the luster of the basic bright nickel layer is notaffected, whereafter finally the chromium layer is applied. Thisintermediate step between the application of the bright nickel layer andthe chromium layer need not necessarily be effected with nickel. It isalso possible to use any other metal, which, however, should preferablynot be more oxidizable than nickel to prevent preferential corrosion ofthe metallic layer interposed between the chromium and the brightnickel. Also, this intermediate step need not be effected by means ofelectrolysis. The intermediate metallic layer may also be appliednon-electrolytically. The organic fibers are kept in suspension by meansof a stirrer or by air circulation or injection.

The invention is illustrated by the following examples, in which ironarticles are subjected to the various treatments.

It should be understood, however, that the examples are merelyillustrative and not intended to limit the invention in any way. It willbe evident that the invention is not, for example, limited to iron asthe base material, since the technical effect is obtained by virtue ofthe microporous chromium structure, which is separated from the baselayer by means of a different layer, mostly nickel, so that a similareffect is obtained with other base materials, such as copper, brass,zinc, aluminum and even synthetic resin materials.

EXAMPLE I BRIGHT NICKEL BATH INCORPORATING NATURAL FIBERS In thisexample there was prepared a bath having the following composition andproperties:

Nickel sulphate 300 g./l. Nickcl chloride 60 g./l. Boric acid 45 g./l.Butine diol mg./l. saccharine 2 g./l. Sodium allyl sulfonate l cc./l.Cellulose fiber BW 200, length about 50 microns, thickness about I7microns 50 g./l. pH 4 Temperature 60 C.

x Cellulose fiber BW 200 is a product sold by Brown Co. of New Yorkunder the name Solca-Floc BWZOO ln this bath an iron article is treatedfor 10 minutes at a current density of 5 a./dm. until a bright nickellayer of 10 microns is obtained on the article, whereafter the articleis plated with a chromium layer of 0.25 microns in a normal chromiumbath. The article has a high brightness and a microporous chromiumstructure.

EXAMPLE II SEMI-BRIGHT NICKEL BATH INCORPORATING NATURAL FIBERS In thisexample there was prepared a bath having the following composition andproperties:

Nickel sulphamate 300 g.ll. Nickel chloride 10 g./l. Boric acid 30 gJl.Formaldehyde 50 mg./l. 2-butene-l,4-diol 20 mg./l. Chloral hydrate I00mgill.

Cellulose fiber, length about 50 microns. thickness about l7 microns 50g./l. P 4 Temperature 60 C.

In this bath an iron article is treated for 10 minutes at a currentdensity of 5 a./dm. until a nickel layer of 10 microns is obtained onthe article, whereafter the article is plated with a chromium layer of0.25 microns in a normal chromium bath. The article has a satin-likeappearance and a microporous chromium structure.

EXAMPLE III MATTE NICKEL BATH INCORPORATING NATURAL FIBERS In thisexample there was prepared a bath having the following composition andproperties:

Nickel chloride 200 g./l. Nickel sulphate I g./l. Boric acid 40 g./l.Cellulose fiber, length about 50 microns, thickness about 17 microns 50g./l. pH 4.5 Temperature 50 C.

In this bath an iron article is treated for 10 minutes at a currentdensity of a./dm. until a nickel layer of microns is obtained on thearticle, whereafter the article is plated with a chromium layer of 0.25microns in a normal chromium bath. The article has a matte finish and amicroporous chromium structure.

EXAMPLE IV BRIGHT NICKEL BATH INCORPORATING NATURAL FIBERS Cellulosefiber BW200 in a concentration of about 100 g./l. in a bath of thefollowing composition produces a cloudy effeet; in a concentration ofI50 g./l., however, a uniform satinlike finish is obtained.

Nickel sulphate I00 g./l. Nickel chloride 200 g./l. Boric acid 45 gJl.Butine diol I00 mg./l. Saccharine 2 g./l. Sodium allyl sulphonate lccJI, Cellulose fiber, length about 50 microns, thickness about 17microns I50 g./I. pH 4 Temperature 60 C.

In this bath an iron article is treated for 5 minutes at a currentdensity of 10 a./dm. until a nickel layer of 10 microns is obtained onthe article, whereafter the article is plated with a chromium layer of0.25 microns in a normal chromium bath. The result is a satin-like orsemi-bright finish and a microporous chromium structure.

EXAMPLE V An iron article is covered with a bright nickel layer of 9microns in the bath of Example I without the cellulose, and then with 1micron of the bath in Example IV. Finally, the article is covered with0.25 micron of chromium. The article has a bright appearance and thechromium layer is microporous.

EXAMPLE VI An iron article was coated with a layer of bright nickel of 9microns by means of the bath of Example I, but without the cellulose,and then with 1 micron of nickel by means of the bath in Example IVcontaining, instead of cellulose fiber, wool fiber in a concentration ofI00 g'./l., the fibers having a thickness of about 20 microns and alength of about 120 microns. Thereafter, the article is covered with0.25 micron of chromium. The result is a microporous chromium structureand a high brightness.

EXAMPLE VII An iron article was covered with a bright nickel layer of 9microns by means of the bath of Example 1 without the cellulose and thenwith 1 micron of nickel by means of the bath in Example IV, containingacetate cellulose fiber instead of cellulose. The fibers have athickness of about 12 microns and a length of about 50 microns, and theconcentration is 125 g./l. Thereafter the article is covered with 0.25micron chromium. The result is a microporous chromium layer of highbrightness.

EXAMPLE VIII An iron article was covered with a layer of 9 microns ofbright nickel by means of the bath of Example I without the cellulosefiber, and then is treated in the following electrolytic bath Cobaltchloride I00 g./l. Sodium Tungstate 4S gJl. Rochelle salt 400 .1!.Ammonium chloride 50 g./l. Nylon fiber thickness 0.5 microns length 20microns 50 g". pH 8.5 Temperature C.

The article is treated for 1 minute at a current density of l a./dm. Thearticle is then plated with 0.25 micron chromium. The result is amicroporous chromium structure of high luster.

EXAMPLE IX An iron article was covered with 9 microns bright nickel bymeans of the bath of Example I without the cellulose fiber, and then wastreated in the following bath without the application of electriccurrent for a period of 2 minutes.

Nickel chloride 30 g./l. Sodium citrate I00 g./|. Ammonium chloride 50g./l. Sodium hypophosphite 20 3.". PVC fiber, thickness 5 microns I00g./|. length 70 microns Temperature 90 C.

pH (with NH OH addition) 9 The article is then covered with a chromiumlayer of 0.25 micron thickness. The result is a microporous chromiumstructure of high luster.

EXAMPLE X CORRODKOTE TEST Article Produced l of rust after cycles byExample I II III IV I O 0 0.] 0.3 II 0 0 0 0.2 III 0 0 0 0.2 IV 0 0 00.1 V 0 0 0 0 VI 0 0 0 0.! VII 0 0 0 0.1 VIII 0 0 0 0.2

IX 0 0 0.1 X0 3 7 X l 3 5 7 Xe 0 0.1 0.5 c8 1 From the above it will bereadily apparent that the surface deposits according to the inventionare more corrosion resistant than the known deposits in which theorganic fibers are absent. Moreover, this increase in corrosionresistance is present even when the nickel base layer of the knowndeposits is increased substantially in thickness.

Thus there can be obtained, according to the invention, a smoothchromium deposit of any desired luster which is highly corrosionresistant and microporous as a result of the incorporation of an organicfiber in 'a nickel layer beneat the chromium layer.

in Examples l-lV the brightness of the bath is a function of thequantity and type of brightness employed. Thus the high brightness ofthe article obtained according to Example I owes its existence to thepresence of butine diol in the bath, while the satin-like appearance ofthe article obtained according to Example [I is the result of thepresence of 2-butene-l,4- diol. The bath described in Example Ill doesnot contain any brighteners so that the article obtained according tothat Example has a mat finish.

The invention is next illustrated in conjunction with the attacheddrawing, wherein:

FIG. 1 is a cross-section view showing a first embodiment of microporouschromium deposit according to the invention; and

FIG. 2 is a second embodiment thereof.

In FIG. 1 there is shown an article 1, having an outer surface on whichis applied a base layer 2. The base layer contains organic fibers 3 ofthe type as mentioned hereinbefore. Applied to the base layer 2 is achromium layer 4 which is conferred with the microporous smooth surface.FIG. 1 represents the article with the deposit thereon, as shown inExamples l-lV.

In FIG. 2 there is illustrated the deposit as shown in Examples 5-9,wherein on the surface of the article 1' there is placed a base layer 5constituted of nickel without organic fibers therein. An intermediatelayer 2 is placed on the layer 5 and in layer 2' are contained theorganic fibers 3. Applied to the outer surface of intermediate layer 2is chromium layer 4'.

The chromium layer 4 or 4' is not closed, but it is microporous. Thismicroporosity is caused by the fibers which are disposed wholly orpartially at the surface of the layer 2 or 2' respectively and servingin that way asinsulators so that at that location no chromium isdeposited. Thus, the deposit by electroplating of the chromium layer isinterrupted where the organic fibers project from the surface of thebase or intermediate layer, whereby the desired microporous structure isobtained for the chromium layer.

Numerous modifications and variations of the disclosed methods of theinvention will become apparent to those skilled in the art withoutdeparting from the scope and spirit of the invention as defined in theattached claims.

What is claimed is:

1. A method of applying a smooth microporous chromium deposit on anarticle, said method comprising: applying to said article a metallicbase layer containing organic fibers of nonconducting materials having alength of from 10 to 30 microns, and thereafter electrolyticallyapplying a chromium layer on the base layer.

2. A method as claimed in claim 1, wherein said fibers are selected fromthe group consisting of natural fibers, semisynthetic fibers andsynthetic fibers.

3. A method as claimed in claim 1, wherein said base layer iselectrolytically deposited on the article in a bath, said organic fibersbeing present in the bath in an amount from 50 to 150 4. A method asclaimed in claim 3, wherein said bath is a nickel bath.

5. A method as claimed in claim 1, wherein said base layer has athickness of 10 microns and the chromium layer has a thickness of about0.25 micron.

6. A method as claimed in claim 1, wherein said organic fiber is presentin the base layer in an amount to provide a surface finish for thearticle which may vary from bright to matte finish.

7. A method of applying a bright, smooth microporous chromium deposit onan article, said method comprising: ap plying to said article a brightmetallic base layer, applying a thin second metallic layer containingorganic fibers of nonconductive material onto said first layer, saidfibers having a length of from 10 to 300 microns and thereafterelectrolytically applying a chromium layer on the second layer.

8. A method as claimed in claim 7, wherein said second layer has athickness between 0.1 and 3 microns.

9. A method as claimed in claim 8, wherein said base layer is a brightnickel layer and said second layer is a nickel layer with said fibers.

10. A method as claimed in claim 8, wherein said second layer is appliedby electrolytically depositing the same on the base layer.

11. A method as claimed in claim 8, wherein said second layer is appliedby immersing the article with the base layer thereon in a treatment bathcontaining the organic fibers suspended therein.

12. A method of forming a corrosion-resistant microporous deposit on anarticle, said method comprising applying on said article acorrosion-resistant metallic base layer having organic fibers of alength from 10 to 300 microns dispersed therein, and applying byelectrolytic deposition a metallic corrosionresistant layer on the firstsaid layer with a thickness substantially less than that of said firstlayer, the second of said layers being rendered microporous by theorganic fibers in the base layer.

13. An article having a deposit thereon, said deposit comprising anelectrically conductive base layer on said article containingnonconductive organic fibers dispersed therein such that at least someof said fibers project through the surface of said base layer, and alayer of chromium on said base layer, the latter layer being interruptedat locations where the organic fibers project through the surface of thebase layer.

14. An article as claimed in claim 13, wherein said base layer is anickel layer having a thickness of 10 microns, the chromium layer havinga thickness of 0.25 microns.

15. An article having a corrosion-resistant deposit thereon, saiddeposit comprising a metallic base layer containing a random orientationof nonconductive organic fibers, said fibers having a length of 10 to300 microns, and an electrolytically deposited chromium layer on saidbase layer, said chromium layer being microporous by virtue ofinterruptions therein caused by the projection of at least some of theorganic fibers from the surface of the base layer.

16. An article having a bright deposit thereon, said deposit comprisinga bright metallic base layer, an intermediate layer on said base layercontaining organic fibers dispersed therein, at least some of whichproject from the surface of the intermediate layer, and a microporouschromium layer on the intermediate layer.

17. An article as claimed in claim 16, wherein said intermediate layeris relatively thin compared to said base layer.

18. An article as claimed in claim 17, wherein said base layer is anickel layer having a thickness of 9 microns and the intennediate layeris also nickel but of a thickness of 1 microns, the chromium layerhaving a thickness of 0.25 micron.

2. A method as claimed in claim 1, wherein said fibers are selected fromthe group consisting of natural fibers, semi-synthetic fibers andsynthetic fibers.
 3. A method as claimeD in claim 1, wherein said baselayer is electrolytically deposited on the article in a bath, saidorganic fibers being present in the bath in an amount from 50 to 150g./l.
 4. A method as claimed in claim 3, wherein said bath is a nickelbath.
 5. A method as claimed in claim 1, wherein said base layer has athickness of 10 microns and the chromium layer has a thickness of about0.25 micron.
 6. A method as claimed in claim 1, wherein said organicfiber is present in the base layer in an amount to provide a surfacefinish for the article which may vary from bright to matte finish.
 7. Amethod of applying a bright, smooth microporous chromium deposit on anarticle, said method comprising: applying to said article a brightmetallic base layer, applying a thin second metallic layer containingorganic fibers of nonconductive material onto said first layer, saidfibers having a length of from 10 to 300 microns and thereafterelectrolytically applying a chromium layer on the second layer.
 8. Amethod as claimed in claim 7, wherein said second layer has a thicknessbetween 0.1 and 3 microns.
 9. A method as claimed in claim 8, whereinsaid base layer is a bright nickel layer and said second layer is anickel layer with said fibers.
 10. A method as claimed in claim 8,wherein said second layer is applied by electrolytically depositing thesame on the base layer.
 11. A method as claimed in claim 8, wherein saidsecond layer is applied by immersing the article with the base layerthereon in a treatment bath containing the organic fibers suspendedtherein.
 12. A method of forming a corrosion-resistant microporousdeposit on an article, said method comprising applying on said article acorrosion-resistant metallic base layer having organic fibers of alength from 10 to 300 microns dispersed therein, and applying byelectrolytic deposition a metallic corrosion-resistant layer on thefirst said layer with a thickness substantially less than that of saidfirst layer, the second of said layers being rendered microporous by theorganic fibers in the base layer.
 13. An article having a depositthereon, said deposit comprising an electrically conductive base layeron said article containing nonconductive organic fibers dispersedtherein such that at least some of said fibers project through thesurface of said base layer, and a layer of chromium on said base layer,the latter layer being interrupted at locations where the organic fibersproject through the surface of the base layer.
 14. An article as claimedin claim 13, wherein said base layer is a nickel layer having athickness of 10 microns, the chromium layer having a thickness of 0.25microns.
 15. An article having a corrosion-resistant deposit thereon,said deposit comprising a metallic base layer containing a randomorientation of nonconductive organic fibers, said fibers having a lengthof 10 to 300 microns, and an electrolytically deposited chromium layeron said base layer, said chromium layer being microporous by virtue ofinterruptions therein caused by the projection of at least some of theorganic fibers from the surface of the base layer.
 16. An article havinga bright deposit thereon, said deposit comprising a bright metallic baselayer, an intermediate layer on said base layer containing organicfibers dispersed therein, at least some of which project from thesurface of the intermediate layer, and a microporous chromium layer onthe intermediate layer.
 17. An article as claimed in claim 16, whereinsaid intermediate layer is relatively thin compared to said base layer.18. An article as claimed in claim 17, wherein said base layer is anickel layer having a thickness of 9 micron and the intermediate layeris also nickel but of a thickness of 1 microns, the chromium layerhaving a thickness of 0.25 micron.